egl: remove unused 'Screens' array from _egl_display

This was used by EGL_MESA_screen_surface that has been removed
in commit 7a58262e58.

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Emil Velikov <eml.velikov@collabora.com>

src/egl/main/egldisplay.h

@@ -168,7 +168,6 @@ struct _egl_display
    char ClientAPIsString[100];                     /**< EGL_CLIENT_APIS */
    char ExtensionsString[_EGL_MAX_EXTENSIONS_LEN]; /**< EGL_EXTENSIONS */
 
-   _EGLArray *Screens;
    _EGLArray *Configs;
 
    /* lists of resources */